Process for manufacturing cutting or piercing instruments



Nov. ,16 1926. 7

A. IGNATIEFF PROCESS FOR MANUFACTURING CUTTING 0R PIERCING INSTRUMENTS Filed J ly 1o. 1925' Patented Nov. 16, 1926.

UNITED. STAT ALEZAIIDER IGNATIEFF, *MOSKAU, RUSSIKQ.

' 'rnocnss non MANUFACTURING cu'r'rme on r nacme rnsraunnnrs."

" Application filed my 10, 1925, Serial No.

Usual instruments for cutting, piercingor shaving bodies become blunt in use, as their cutting angle becomes greater owing to the .wearand tear which is the greatest at theedge and decreasesagainst the other. parts. Resharpening therefore must be effected by grinding or the like.

The mvention consists in forming the points or cutting edges of diiferent mate.- rials in such manner, that the hardness on every single spot essentially corresponds to the load and wear to be sustained on said spot. Thereby the whole surface. near the cutting edge is uniformly worn out, which means that the cutting angle remains un-J altered and the instrument remains sharp.

The diflferent layers of material'can be produced, for instance by using a steel'with much carbonor other hardening substances and. correspondingly high hardening facul- "ties and depriving this steel, on the spots of less and less wear, of greater and greater parts of its carbon content; thus the hardness becomes the greatest at the cutting edlge e or point and diminishes according to t wears. With special advantage it is possible to compose the instrument of single layers or sheets andto unite them by welding, electrolytic deposition or spouting (for instance in the processes of Meurer or Schoop) in this case the hardness and thickness of the layers can be very correctly measured. 7 v

The invention is illustrated in the drawing by way of examples;

Fig. 1 is a cross-section of a usual knife, in which byfdash and dotted lines the shape arising by wear is shown; I

Fig. 2 1s a cross-section of asimilar knife made according'to the invention;

Fi 3- is a cross-section of an unsymmetric knife, for instance for shears;

Fig. 4 is a point view (if a needle;

Fig.5 is a cross sect-ion of a knife of the new kind after being worn out; and

Fig." 6 is a similar section, the knife be ng ground. I I

According to Fig. 1 the surfaces 1, 2 of the usual knife include the small cutting angle. In the use the shaded part 3 is worn out, so

that the cutting edge is formed by the dash and dotted line 4, the front part of which furnishes a very blunt cutting angles Accordin to Fig. 2 the new knife consists fiard layer 5 which here lies"in of a ve v the mid tfie plane and to which gradually 42,861, and. in qerjmany Au ua a, 1924.

ESQPATENT, oFFIcE. J

weaker layers 6 =to-1 'l are applied on both 1 sides. These layers may .have for usual instruments a gaugeof 0,1 mm., orfor-specially fine knives a'gauge of 0,01 mm. They'are separately manufactured of the adapted more or less hard steels and welded together by any known process. 4 H It is also possible to manufacture the strongest layer 5 separately and deposit-the other. layers 6 to 11 electrolytically. Thereat by constant altering the com osition of the bath the entire deposit can e produced as a coherent body, the bar which decreases outwardly. It is a so posess of.

sible to deposit the layers one after another 1 in diiferent baths ofdiflerent compositions. In a similar way on the strongest layer 5 the further layers maybe added by a metal spouting apparatus, the difierent 'h'ardnesse's being attained by differently 'heating the metal (between 'meltin'gand half Warm temeratures on the depositin spot); or diferentl hard metalsor a oy'smay be de-,

po ite According to Fig. ablade for shears or chiselsycomposedin the process of the inrounded by wear. This causes no damage as- ;vention', has the hardest layer 5 on one side, K

.a knife or needle, on

at all the steps formed by the single layers are very small- Where absolute smoothness is necessary, the fine steps can be ground flat, or the layers must beproduced. with constantly'decreasinghardness as above described in relation to electrolytic and metal spouting processes (Fig.6).

I claim: j A process of manufacturing cutting and piercing; instruments in a known wayby. welding, electrolytically, 'or casting, and forming thereby cutting edges or points of several layers of different materials of different grades of hardness consisting therein, that at least five layers of thickness not exceeding 1 mm. are used in suchmannerthat the hardnessatdifferent spots corresponds to the stresses and wears arising in the use.

In witness whereof I aflix my-signature.

ALEXANDER IGNATIEFF, 

